Method of making thermoplastic covers



Dec. 6, 1949 s. H. MAGlD METHOD OF MAKING THERMOPLASTIC COVERS 4Sheets-Sheet 1 Filed Aug. 11, 1947 kgzi j.

. IN V EN TOR. SIDNEY H. MAG/D.

BY ATTO/EWE Y Dec, 6, 1949 s. H. MAGID METHOD OF MAKING THERMOPLASTICCOVERS 4 Sheets-Sheet 2 Filed Aug. 11, 1947 INVENTOR.

S/DNEY h. MAG/0.

ATTORNEY 1949 s. H. MAGlD 2,490,451

METHOD OF MAKING THERMOPLASTIC COVERS Filed Aug. 11, 1947 4 Sheets-Sheet3 SIDNEY H. M/IG/D.

E r 11. INVENTOR.

S. H. MAGID METHOD OF MAKING THERMOPLASTIC COVERS I Dec 6, 194.9

4 Sheets-Sheet 4 Filed Aug. 11, 1947 HILL,

INVENTOR. SID/Vt) HIV/967D.

ALL/ppm Patented Dec. 6, 1949 METHOD OF MAKING THERMOPLASTIC COVERSSidney H. Magid, Larchmont, N. Y. Application August 11, 1947, SerialNo. 767,994

17 Claims.

This invention relates to improved protective coverings for dishes,jars, bowls, the human head, etc. and to a method for making the same.Reference is here made to my Patent No. 2,466,643.

The protective coverings of the type with which the present invention isconcerned have heretofore been made by sewing a drawstring or webelastic band to or into a tunnel or hem around to a suitably cut blankof material, usually a transparent plastic material. In addition tobeing time-consuming, the previous method of fabrication does notproduce a durable product since the drawstring or fabric elastic bandfrequently becomes loose or tears away from the plastic material withcontinued use and stitchin tends to weaken the material. Accordingly, itis an object of the present invention to provide a rapid method offabricating a protective covering of the character indicated, theprotective covering having improved qualities of strength anddurability.

A further object of the invention is the provision of a method wherebyan elastic band of rubber or the like or other constricting band may bepositioned adjacent the marginal edge of a blank of thermoplasticmaterial, the thermoplastic material being then folded or squeezed aboutthe band to form contiguous, adjacent plies thereabout, heat being thenapplied to the contiguous plies or layers of thermoplastic material toseal the elastic band therewithin.

An additional object of the invention is the provision of a method ofthe character indicated wherein the thermoplastic material from whichthe protective coverings are formed, may be fed from a web or sheet intimed sequence with the operation of a blank-cutting and heat-sealingmeans for'rapid and eflicient production of the protective coverings.

The foregoing objects, as well as additional objects and advantages ofthe invention will be readily apparent in the course of the followingdetailed description taken in connection with the accompanying drawingswhich illustrate several embodiments of the invention, and wherein:

Fig. 1 is a front elevational view of a device for forming protectivecoverings from precut blanks of material.

Fig. 2 is a plan view of a circular blank or disc of thermoplasticmaterial from which the protective covering may be formed.

Fig. 3 is a bottom plan view of a finished protective covering.

Fig. 4 is a sectional view taken along line 4-4 of Fig. 3, showing theelastic band sealed between the contiguous folds of the thermoplasticmaterial.

Figs. 5 to 9 are fragmentary views illustrating the sequential steps inthe formation of the protective covering using the device of Fig. 1.

Fig. 10 is a fragmentary detail view of a modified form of deviceemploying depressible clearance sections facilitating the convenientremoval of the sealed protective covering.

Fig. 11 is an elevational view of a modification of the apparatus forforming the protective coverings directly from an intermittently fedroll of thermoplastic material.

Fig. 12 is a top plan view of the apparatus of Fig. 11. I

Figs. 13, 14 and 15 are fragmentary detail views illustrating sequentialsteps in the formation of the protective coverings using the apparatusillustrated in Figs. 11 and 12.

Fig. 16 is a schematic wiring diagram showing the relation of theswitches to the motor circuit.

The protective coverings of the invention which, for convenience, willhereafter be referred to as bowl covers, may be made from any suitablethermoplastic material, as for instance, vinyl resin sheeting, orpolyethylene and the like. In the practice of the invention using thedevice illustrated in Fig. 1 and Figs. 5-10, the thermoplastic materialis pre-cut in any suitable man ner to form a circular blank or disc ID,as shown in Fig. 2.

The device upon which the disc I0 is formed into a bowl cover comprisesa suitable framework upon which is mounted a reciprocable forming platel2, which may be actuated by a valve-controlled air cylinder I3 or othersuitable means. A centrally positioned cylindrical die base I4 is fixedto framework H below forming plate l2, for the reception of a movabledie head l5, said die head being activated toward and away from die baseH by a valve-controlled air cylinder I 6, or other suitable means. Diehead I5 is formed adjacent the top thereof with an annular recess I Ifor a purpose to be fully described hereinafter.

A depressible positioning plate I8 having a central aperture to' exposedie head I5 is also I mounted on framework ll intermediate die head l5,and forming plate l2. Springs l9 serve to normally retain plate l8 inraised position (Fig. 1). Plate 18 carries a guide ring 20 which servesto properly center and locate the thermoplastic disc In with respect tothe die head I 5. Forming plate I2 is provided with a forming ring l2awhich is preferably beveled downwardly and outwardly 3 as shown at no inFig. 1. Electrical conduits Ila and its connect die base It and die headIi respectively to a high frequency source.

in iormmg the above covers, the pre-cut thermoplastic (115C or blank Itis placed on positioning plate I8 within guide ring 20; shown in Figs. 1and 5. The valve control (not shown) for cylinder i3 is then operated tobring down forming plate l2 against positioning plate It, as shown inFig. 6. The continued downward movement of forming plate l2 carriespositioning plate i8 below the level of die head it to simultaneouslybring disc in to rest against the top of die head l5 and to form adepending skirt Ila down around said die head, as clearly shown in Fig.7. An elastic band 20 of rubber or the like is then applied around thethermoplastic disc III at the level of the annular groove II in die headIt.

As clearly shown in Fig. 9, elastic band 2| contracts the thermoplasticmaterial of the depending skirt into the annular groove II, the band 20to be contained finally within adjacent contiguous folds of the disc l0,and restin against the limiting element lid. The skirt lid of disc I ispermitted to flare outwardly by the presence of the bevel no on formingring In of forming plate l2.

The valve-control for cylinder I3 is next operated to return formingplate I! to the initial position (Fig. 1) thereby also releasingpositioning plate i8 which is urged to its initial rest pos.tion (Fig.i) by means of springs It. It will be noted that after the return of.forming plate l2 and positioning plate I! to their respective restpositions above die head It and die base It the disc ill will be held todie head I 5 by means of the elastic band 20 applied within annulargroove II.

The valve control (not shown) for cylinder I6 is next operated to movedie head downwardly toward die base H, thereby firmly squeezing togetherthe doubled-over folds of the thermoplastic disc l0 within groove l1 andenclosing band completely within said doubled-over folds. Electricalenergy is simultaneously applied to the doubied-overfolds of disc l0outwardly of elastic band 20 and between the closely adjacent surfacesof die head l5 and die base II, to completely seal the elastic band 20within said doubled-over folds. The valve control for cylinder I5 isnext operated to bring die head I! up to its original position (Fig. 1)away from die base I, after which the finished article may be removedfrom said die head by depressing slightly positioning plate l8.

Upon removal of the finished article from die head IS the elastic band20 will contract to its normal diametral size to produce the bowl cover2| (Fig. 3) which is in the form of a flexible hollow body ofthermoplastic material having an openin of variable diametral size byreason of the presence of the elastic band 20 sealed within thecontiguous doubled-over folds of thermoplastic material, as shown at 22in Fig. 4.

Fig. 10 illustrates the use of a depressible clearance section inpositioning plate lib for facilitating the removal 'of the finishedprotective covering having the elastic band 20 sealed within thedoubled-over folds thereof. A portion of positioning plate I8!) is cutaway to allow mounting of depressible clearance sections Ila. Plate llbmay have fixed thereto a pair of L-shaped. depending bracket supports25. Clearance section Ila may be mounted on pins 26 passing through thebase of eachbracketsnpport 25, said clearance section being depressibleagainst the action of lightweight springs 21 interposed between each ofsaid clearance sections and the base of each bracket support 25. Ifdesired. a pair of such clearance sections Ila may be positioned ondiametrically opposite sides of die head I for my removal of thefinished bowl cover without the necessit of depressing the entirepositioning plate II as is required in the apparatus of the initialembodiment.

Referring now to the embodiment of the invention illustrated in Figs. 11to 15, there is illustrated an arrangement for intermittently feeding aroll of thermoplastic material to a combined blank-cutting and formingdie in timed sequence with the operation of said die. The die may beconsidered as comprising three portions:

(A) A cylindrical die base fixed to the frame of the apparatus.

(B) A sealing die head mounted above said die base and forming, togetherwith the die base, an annular groove therewithin.

(C) A cutting and forming die portion movable toward and away from saiddie base and sealin head for intermittently feeding and forming cutblanks of thermoplastic material.

The thermoplastic material is intermittently fed past the cutting dieportion of the die assembly in timed sequence with the operation of thedie assembly as by means of a motor-driven roller system, the rollersystem being actuated at the termination of the upstroke of the cuttingdie as by means of a circuit-closing switch and a rotary contact brush.A pair of laterally disposed arcuate forming members is arranged toreciprocate at the beginning of the upstroke of the cutting die to forcethe plastic material within the annular groove of the sealing die head,thereby preparing the material, more readily to receive the elastic bandand to hold said material in the groove prior to the application of theelastic band over the plastic material within the groove and the finalsealin operation.

Fig. 11 shows the framework II upon which is mounted the cylindrical diebase 3| carrying the movable sealing die head 32. Die head 32 forms anannular groove 33 with base SI and is actuated by a valve-controlleddouble acting air cylinder 3|.

Electrical conduits Sla and 32d connect the die base 3| and the die head32 with a high frequency source.

Cutting and forming die portion 35 rides on pins 36 secured at theirlower ends to framework 3! and at their upper ends to a top plate 31.Cutting die portion 35 may be actuated by a doubleactingvalve-controlled air cylinder 38 fixed to top plate 31 or by othersuitable means.

A roll of thermoplastic film material 3!, a motor 40, a pair of feedrollers ll and a pair of take-off rollers 42 may be mounted on frameportion 30a at a suitable level above sealing die head 32 and die base3|. Thermoplastic film 39 is fed past the cutting die portion 35 bymeans of the intermittently actuated motor ll in time sequence with thecompletion of the upstroke of said cutting die portion so that a freshportion of film will be positioned therebeneath for cutting a new blankby the outer peripheral cutting edge 35a. One convenient manner ofobtaining the proper intermittent feed of thermoplastic film is by means15 of spring switch contacts lib secured to the cutting die portion 33and 31b secured-to the top plate 31 said contacts forming a part of theelectrical circuit to the motor for actuating the roller system. Contact33b may be rigid while contact 3'") may be a flexible arm. The upper orinner side of contact 31b may carry a piece 'of insulation 31c sothat-as the cutting die moves downwardly, the contact 35!) will contactthe insulation 31c and because of the flexibility of contact 31b,contact 35b will-wipe past contact l'lb without closing the motorcircuit. However, when die 35 moves upwardly contact 3512 will close themotor circuit as it is wiping past contact 31b and the motor will thenturn rotary contact 50 so that brush 5| rides on the metal band I2, thusmaintaining the motor circuit closed until the insulation insert 53again reaches the brush II at which time the motor circuit is broken.Any other conventional arrangement maybe used for attaining this resultother than the momentary contact arrangement at the termination of theupstroke of cutting die portion 35.

' A pair of arcuate forming members 43 is provided for cooperation withthe annular groove 33 formed by sealing die head 32, and die base 3|, toform a blank of thermoplastic material about said die head in a mannerto be fully described here in below. Each of the arcuate forming members43 may be actuated simultaneously by a valve-controlled air cylinder 44or other suitable means. I

In actual operation of the apparatus, valvecontrolled cylinder 38 isactuated to move cutting punch 35 downwardly past frame portion 30a,which has cutting die opening 30b and toward die head 32. Simultaneouslywith the downward motion of cutting die punch 35, a blank 33a ofthermoplastic material is cut from the thermoplastic film 39 (Fig. 13).The diameter of cutting edge 35a is greater than the diameter ofdle headwith sufficient material remaining to form a skirt portion 391) (Fig.14) Y Arcuate forming members 43 are actuated by valve-controlledcylinders 44 at the beginning of the upstroke of cutting die punch 35securely form skirt portion 39b down around die head 32 and to force aportion of said skirt within annular groove 33 to conform therewith(Fig. 15). An elastic band (not shown) may then be applied within theannular groove 33 over the skirt portion 39b. The arcuate members .43are then withdrawn through instrumentality of cylinders 44 and cylinder34 may then be actuated to move sealing die head 32 downwardly tosqueeze the doubled-over folds about the enclosed elastic band andheating energy is then applied through the contiguous doubled-over foldsto seal the elastic band therewithin. After sealing, the cylinder 34 isoperated to raise die-head 32 to its initial raised position away fromdie base 3| in order that the finished, thermoplastic bowl cover may beremoved, the cover (upon contraction of the elastic band) assumingsubstantially the form and structure illustrated in Figs. 3 and 4 inconnection with the initial embodiment of the invention.

It is apparent from the foregoing that the invention provides animproved method for forming a bowl cover or other protective covering ofthermoplastic material having a flexible hollow body provided with anopening of variable size. Various types of protective coverings may beproduced by the practice of the invention, for

example, protective coverings for bowls, dishes, jars, and the like,bathing caps. etc.

.ent, is:

1. The method of making a protective covering of flexible thermoplasticsheet material having an expandable opening, with the aid of a form,which has an annular groove therearound, and an elastic constrictingelement; said method comprising positioning said material over said'form and past said groove, applying said element under-stretchedcondition over the material opposite said groove; and releasing saidelement to permit it to contract tov draw a portion of said materialinto said groove to form a dou-, bled-over fold of thermoplasticmaterial around said element, then pressing together the entiredoubled-over fold, then heat-sealing said doubled-over fold to confinesaid element therein.

2. The method described in claim 1, in which the pressing together ofthe entire doubled-over hem or fold is done simultaneously.

3. The method described in claim 1, in which the heat-sealing of theentire doubled-over hem is done simultaneously.

4. The method described in claim 1, in which the pressing together ofthe entire doubled-over hem or'fold is done simultaneously, and theheatsealing of the entire doubled-over hem is done simultaneously.

5. The method described in claim 1, in which the pressing together andthe heat-sealing of the entire doubled-over hem are done simultaneously.

6. The method of making a protective covering of flexible thermoplasticsheet material aving an expandable opening, with the aid of. a form, andan elastic constricting element; said method comprising positioning ofsaid material over said form, applying said element over said materialadjacent the peripheral edge thereof, then forming a doubled-over foldaround said element, then pressing together the entire doubled-overfold,

then heat-sealing said doubled-over fold to confine said elementtherein.

7. The method described in claim 6, in which the doubled-over folding ofthe entire peripheral portion of the material is done simultaneously.

8. The method described in claim 6, in which the pressing together ofthe entire doubled-over hem or fold is done simultaneously.

9. The method described in claim 6, in which the heat-sealing of theentire doubled-over hem is done simultaneously.

10. The method described in claim 6, in which the doubled-over foldingof the entire peripheral portion of the material is done simultaneously,and in which the pressing together of the entire doubled-over ham orfold is done simultaneously.

11. The method described in claim 6, in which the doubled-over foldingof the entire peripheral portion of the material is done simultaneously,in which the pressing together of the entire doubled-over hem or fold isdone simultaneously, and in which the heat-sealing of the entiredoubled-over hem is done simultaneously.

12. The method described in claim 6, in which the doubled-over foldingof the entire peripheral portion of the material is done simultaneously,

and the heat-sealing of the entire doubled-over hem is donesimultaneously.

13. The method described in claim 6, in which the pressing together ofthe entire doubled-over hem or fold is done simultaneously, and theheatsealing of the entire doubled-over hem is done simultaneously.

14. The method described in claim 6 in which the pressing together andthe heat-sealing of the v entire doubled-over hem are donesimultaneously.

15. The method of making a protective covering of flexible thermoplasticsheet material having an expandable opening, with the aid of a form andan elastic constricting element,'said method comprising positioning ofsaid material over said form, applying said element over said materialadjacent the peripheral edge thereof, then forming a doubled-over foldsimultaneously around the entire peripheral portion of said element, andthen uniting said doubled-over fold to confine said element therein.

16. The method of making a protective covering of flexible thermoplasticsheet material having an expandable opening, with the aid of a form andan elastic constricting element, said method comprising positioning ofsaid material over saidv ing an expandable opening. with the aid of aform which has an annular groove therearound, and an elasticconstricting element; said method comprising positioning said materialover said form and past said groove, applying said element understretched condition over the material opposite said groove, forming adoubled-over fold of thermo-plastic material around said element, byreleasing said element to permit it to con. tract to draw a portion ofsaid material into said groove, then uniting said doubled-over fold toconfine said element therein, said uniting oi the entire doubled-overfold being performed simultaneously.

, SIDNEY H. MAGID.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 169,408 Brown --Nov. 2, 18751,544,312 Gray June 30, 1925 1,997,738 Maxedon --Apr. 16, 1935 2,080,108Brandstein --May 11, 1937 2,125,495 French --Aug. 2, 1938 2,266,459Gilbert --Dec. 16, 1941 2,289,618 Young --July 14, 1942 2,379,357.Humphrey June 26, 1945 2,386,147 Sidebotham ..Oct. 2, 1945 2,424,558Delano --July 29, 1947 2,432,662 Gardner --Dec. 16, 1947

